I need to put a circuit into a pen to turn on and off an LED using 3 AG3 or LR41 batteries connected in series. The LED will be on the tip of the pen and the switch will be on the side surface of the ...

A few days ago, i bought this remote-conrolled light switch. When installing it, i wondered why i had only two lines to connect (the one going to AC power and the one to the lamp); i thought i needed ...

I'm building a boombox, and it needs a couple of switches for main on/off, voltmeter on/off and LED lights on/off. Since I don't have any metalworking tools I am going to buy a premade front panel, ...

I have two batteries. I would like a circuit which looks at their voltage, and puts them in parallel if they are the same. If they are not the same, the one with the higher voltage should be taken out ...

I am wanting to use a 4066 chip to control current flow through a circuit.
(data sheet for the chip - http://www.ti.com/lit/ds/symlink/cd4066b.pdf)
I will be inputting 3.3v into the control pins as I ...

For reasons beyond explanation, I'm trying to source an industrial limit switch to control the power to a desktop PC. It's run on a switch mode standard computer PSU.
Most of the limit switches I've ...

I'm installing a three way dimmer on a 3 switches line for a light.
In the dimmer notes the installation is done by replacing the three way switch on the load side.
Can I replace the one at the line ...

I am trying to operate a 5V solenoid using a IRLZ44N power MOSFET.
My problem is I cannot get the MOSFET switch to work.
My circuit: 5V into solenoid and diode (1n4004) in parallel into the drain of ...

I am trying to bias the filament of an electron gun to -575 V, but I need to switch it on and off using a TTL signal. I have an idea for how to do it, but I would like to know if it will work before I ...

I would like to send wake up and halt signal to a linux board. I just want simulate the power button on the board so I will replace it with a circuit.
So: When I the car's ignition line is on it has ...

I have designed a board with a SoC (I.MX6) and a PCIe switch (PEX8605), everthing it's working in the board exept the PCIe switch, we can't even recognise it with lspci, dmesg..., so I wanna check if ...

I have a DC switch that is being used as the main power switch for an audio amplifier project I am working on. The schematic is shown below. (a few things are wrong with that circuit, but have since ...

I want to make a controller for Wound Rotor Induction Motor in which effective external resistance on rotor side is varied by changing the duty cycle(PWM controller) with the help of a chopper.What ...

I designed the bidirectional switch seen below. But right after, I realized that it would only work with resistive loads. However I want this to be a general purpose product, which will also control ...

i'm new here and my knowledge in electronics is basic, so what i'm trying to do is to switch between two power sources, one at 5V an other at 12V, i already made a circuit that kinda works, but i have ...

I'm making a little test board with a switch that intend to plug into a popular southern European microcontroller system. Obviously, it's intended to plug into a pin which is configured for input, but ...

Do potentiometer packages exist that include 2 double-pole double-throw switches, one of which is switched at the lower limit, the other switched at the upper limit? (Preferably with tactile clicks.)
...

I have a red laser pen module:
http://space-linker.com/Uploadfiles/UploadFile/2010178127739.jpg
I want to be able to have it always on.
How can I short the button, without having to glue or tape it ...

I need to build a wireless switch (preferably RF) for a LED and possibly trigger a sounded alert using a transmitter and receiver pair and it needs to have a range with a strict maximum of 2 meters. ...

I'm trying to translate a circuit I made from breadboard to PCB and need some help finding out what components I should be looking for.
Basically, so far I have a very simple circuit running 12V AC, ...

I'm looking for a high current DC switch (able to switch something like 5V@30A) and I've encountered several DPDT that might do what I need, however they are only rated for AC applications (3A@250VAC ...